fix(http): Fix error message when we call jsonp without importing HttpClientJsonpModule (#38756)

Currently, when we call jsonp method without importing HttpClientJsonpModule, an error message appears saying
'Attempted to construct Jsonp request without JsonpClientModule installed.' instance of 'Attempted to
construct Jsonp request without HttpClientJsonpModule installed.'

PR Close #38756

Author: wKoza

packages/common/http/src/xhr.ts

@@ -79,9 +79,10 @@ export class HttpXhrBackend implements HttpBackend {
    */
   handle(req: HttpRequest<any>): Observable<HttpEvent<any>> {
     // Quick check to give a better error message when a user attempts to use
-    // HttpClient.jsonp() without installing the JsonpClientModule
+    // HttpClient.jsonp() without installing the HttpClientJsonpModule
     if (req.method === 'JSONP') {
-      throw new Error(`Attempted to construct Jsonp request without JsonpClientModule installed.`);
+      throw new Error(
+          `Attempted to construct Jsonp request without HttpClientJsonpModule installed.`);
     }
 
     // Everything happens on Observable subscription.